Final answer:
Excessive clearance between the linings and drums in a braking system can be caused by wear and tear, misadjustment, and drum deformation. It should be repaired by a qualified mechanic.
Step-by-step explanation:
The excessive clearance between the linings and drums in a vehicle's braking system may be caused by several factors:
- Wear and tear: Over time, the brake linings and drums can wear down, resulting in increased clearance. This can happen due to the normal use of the brakes or from the accumulation of debris, rust, or corrosion.
- Misadjustment: If the brakes are not properly adjusted, it can lead to excessive clearance. When the brake shoes are not properly positioned, they may not make sufficient contact with the drum, resulting in an increased clearance.
- Drum deformation: If the brake drum becomes distorted or out-of-round, it can cause excessive clearance. This can happen due to overheating, excessive use of the brakes, or poor quality materials.
To address the excessive clearance, the brake system should be inspected and repaired by a qualified mechanic. They may need to replace worn linings and drums, adjust the brakes, or address any other underlying issues.